I noticed that if you’re stuck with dozens of ugly loaches to sell, asking Flamey to burn them first significantly increases the selling price!

It works for other items as well. I don’t know if burning increases the selling price for every flammable item, this is just a few that I’ve tried and run the numbers on. Before you go chucking everything into the fire, keep in mind that a lot of items have other uses where they might be even more valuable (like crafting or feeding imps).

Here’s how to read the chart:
New item produced by burning = $price
Original item- $original price > # of new item > $total new price > $profit (%profit)

Charred fishbones = $50
Flatfish- $50 > 2 bones > $100 > 50 (100%)
Ugly loach- $13 > 1 bone > $50 > 37 (285%)
Leatherskins- $25 > 2 bones > $100 > 75 (300%)
Shadowmouth- $25 > 1 bone > $50 > 25 (100%)

Root vegetables = $100
Parsnip- $400 > 15 RV > $1500 > 1100 (275%)
Turnip- $100 > 9 RV > $900 > 800 (800%)
Potato- $20 > 3 RV > $300 > 280 (1400%)

Roasted mushrooms = $240
Brown mushroom- $50 > 1 RM > $240 > 190 (380%)
Red mushroom- $100 > 2 RM > $480 > 380 (380%)